The invention relates in general to metal treating systems and in particular to a new and useful band store or storage system for bands/belts running through guide passages continuously, in particular metal bands, in treatment systems, with at least two movable loop carts or guide or guide reel carriages and loop cart drives.
In the inlet and outlet of band treatment systems for e.g. paper bands, plastic bands, metal bands or the like, with continuous operation in a process section, it is necessary to provide a band storage area which bridges the down times when changing ties or bundles. In the treatment of metal bands, the process section may be e.g. a stretching installation, a pickling installation, a galvanizing installation and a paint coating installation etc. It is known to provide band stores which extend horizontally and comprise one or more loop carts or so-called loop cart band stores. The loop carts are movable horizontally and usually arranged one above the other. The speed of the loop carts is determined by upstream or downstream connected tension roller sets, and the loop carts are run traction or force controlled via winches. In high speed treatment installations, e.g. pickling installations, the available installation length is normally not sufficient for running with one loop cart only. For this reason, two or more loop carts are arranged one above the other, in particular at the infeed and, due to the welding together of metal bands to be joined, relatively long down times must be bridged. Since in the known forms of construction all loop cart drives are traction controlled, that is according to the force (tensions) or load experienced by the loop cart as a result of band tension, the desired synchronization of the loop carts does not exist because the loop carts are under different loads. In the extreme case, one loop cart alone can run at double the speed, and only after this loop cart is in the end position will the next loop cart run to its end position at double the speed also. Owing to this, retractable band supporting rollers normally installed in the band store are retracted so fast that damage will occur. The attempt has been made to remedy this deficiency by reducing the winch cable tension of the respective preceding loop cart. But since, e.g. in a pickling installation, very different band dimensions and band strengths are run successively, asynchronous running of the loop carts again results as the joints, or weld seams, of such different metal bands are being passed.
Lastly, the procedure has been adopted to couple the loop cart drives, or their winches, by means of a connecting shaft, to ensure synchronism. This solution, a costly one is not satisfactory either, since due to unequal conditions or loads of the loop cars their transmissions are also differently stressed. In particular in case of blocking of a loop cart damage to the transmission must be feared, because then the power of the loop cart drives or cable winch drives must be absorbed by a single loop cart drive or winch drive.